The number of newly confirmed COVID-19 cases in North Carolina is rising again, with more than 27,600 new cases reported in the last week, state data shows.
But that number, up 16% from the previous week, doesn’t tell the whole story. With all of these take-home tests on the market, people who get sick don’t necessarily report the results to the state Department of Health and Human Services.
A number of numbers that public health officials are keeping a close eye on involve wastewater monitoring.
“We’re seeing much higher numbers, and we’re seeing those numbers really increasing over time in a lot of our urban locations,” Rachel Noble said. She directs the wastewater monitoring laboratory for the state at UNC Chapel Hill’s Institute of Marine Sciences in Morehead City.
After the omicron spike earlier in the year, the amount of the COVID virus Noble found in the sewage samples dropped to almost zero. But in the last few weeks, those numbers have risen again.
“This week’s rate of increase in numbers is higher, which means not only are the numbers increasing, but the rate at which they are increasing is getting faster,” she said. “That’s worrying.”
Noble’s job is to take sewage samples from more than two dozen North Carolina sites, figure out how much coronavirus is in the systems, and identify which variants people are infected with.
“This is based on the idea that infected people shed COVID in their feces. The feces go into the treatment plant, when they flush the toilet, the treatment plant, then we measure the inflow,” Noble explained.
“So we measure all members of the community in that particular sample. We can do a pretty good job of detecting infected people, even in very small samples,” she said.
The DHHS COVID-19 Dashboard provides weekly results from wastewater samples from 26 North Carolina water treatment plants.
The latest available data shows that virus levels have increased by 100% or more in nine of these locations over the past two weeks.
Ten counties in North Carolina, mostly in the Triangle area, are now in the “yellow zone” of COVID with an intermediate risk of community spread, according to the Centers for Disease Control and Prevention. That’s the last two weeks. The rest of the state remains green, with a low risk of community sprawl.
Hospital admissions remain low, with 636 people admitted for COVID-19 in North Carolina in the last week, according to DHHS data. But that’s more than 20% up from the week before.
The CDC’s County Community Risk Index takes into account several factors, including the number of new cases, available hospital beds, and other factors.
Noble said their wastewater samples showed that rural areas are doing better than cities in this recent increase.
Urban areas, she said, have “more people, more kids in the school system, more people interacting in the grocery store and in all places where people interact, and more opportunities to share the virus.”
“It’s a really interesting dynamic that we’re studying,” Noble said. “If there are things in the rural environment that we can use. Maybe people are more outside. People in this area are out on the beach and on their boats.”
She said she is looking to June to see how this recent spike in case counts will fall again or continue to rise.
“It remains to be seen how long this increase will last. We’re getting into the summer months here and as people get more outdoors, school will be phased out soon, so maybe that will ease some of the pressure we’re seeing on the rise in infection rates,” she said.
But Noble said, “If a significant number of people in a city are already infected, you already have a mechanism to infect others.”